Protective devices such as ground fault circuit interrupters (GFCIs) are well known in the art. Their intent is and always has been to protect the electrical power user from electrocution when hazardous ground fault currents are present.
Historical problems with these protective devices include the possibility of line/load miswiring in the field by an installer or the eventual failure of the solenoid driving device, typically a silicon controlled rectifier, which causes the interrupter device to become inoperable while electrical power is still present, even under hazardous ground fault conditions. A variety of methods are used to prevent or attempt to prevent miswiring with varying levels of success. Preventing the problems associated with a defective solenoid driving device is inherently more difficult. Labels and installation instruction sheets have been used to prevent miswiring, but can be ignored by the installer. Solenoid burn-out has been revealed by testing the protective device with a test button, but the result of the test can be ignored by the user.